Dec 16, 2025 · All the matter in the universe is composed of the atoms of more than 100 different chemical elements, which are found both in pure form and combined in chemical compounds.

6 days ago · Cooking, fermentation, glass making, and metallurgy are all chemical processes that date from the beginnings of civilization. Today, vinyl, Teflon, liquid crystals, semiconductors, and …

CHEMICAL meaning: 1 : of or relating to chemistry; 2 : working by means of chemicals

Nov 30, 2025 · Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.

Nov 29, 2025 · A chemical element is any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all …

SPEAKER: Water is an interesting substance with a chemical makeup that gives it some unique physical properties. A water molecule has an oxygen atom with two hydrogen atoms connected to it by …

The substances in a chemical reaction may be chemical elements, molecules, or compounds. The substances present at the start of a chemical reaction are called the reactants; the substances …

Dec 3, 2025 · An atom of sodium (Na) donates one of its electrons to an atom of chlorine (Cl) in a chemical reaction, and the resulting positive ion (Na+) and negative ion (Cl−) form a stable ionic …

Chemical reactions differ from physical changes, which include changes of state, such as ice melting to water and water evaporating to vapor. If a physical change occurs, the physical properties of a …

Dec 22, 2025 · Periodic table, in chemistry, is an organized array of all the chemical elements in order of increasing atomic number. When the elements are thus arranged, there is a recurring pattern in …